1) Field of the Invention
The present invention relates generally to a process for improving the utilization of feedstuffs by ruminants, especially during the transition from a roughage diet to a feedlot diet, and more particularly to a process for administering to a ruminant a feed additive composition which includes lactic acid producing bacteria and lactic acid utilizing bacteria for improving the production from, and feed conversion efficiency of, a high grain or concentrate feedlot diet.
2) Description of the Related Art
Acute indigestion resulting from the transition from a predominantly roughage diet to a feedlot diet could be fatal to ruminants. The purpose of a feedlot operation is to fatten a ruminant, such as beef cattle, for sale or slaughter. The most common and efficient method of fattening ruminants is to feed them a high grain or high energy concentrate diet. However, this abrupt conversion from a roughage or pasture diet of plant food, mainly cellulose, to a feedlot diet predominantly composed of grains and starches can cause decreased production to feedlot cattle and even death from acidosis. Similar diet transitions can result in a decrease in milk production for dairy cows as well as death.
As discussed in Diseases of Feedlot Cattle, Second Edition, Lea & Febiger, p 292-293 (1971), acute indigestion in cattle is caused by sudden consumption of large amounts of grain, green corn, green apples or other easily fermentable feeds. During a roughage diet, cellulosic bacteria predominates in ruminal microflora. Volatile fatty acids are usually formed in the following proportions: acetic, 67%; propionic, 19%; and butyric, 14%. These acids constitute an important nutrient from cellulose digestion. However, during the fattening process at the feedlot, cattle are placed on a high grain diet. On a high grain diet, the ruminal microflora ferment the new feed and produce 100 or more milli-moles per liter of lactic acid resulting in the rumen becoming immobilized. A large portion of the lactic acid accumulated may be the D(-) isomer which is an unavailable energy source for the ruminant and thus builds up in the rumen. Absorption of the acid into the blood lowers the blood pH and diminishes the content of bicarbonate and glucose bringing about acidosis. Compensation for the acidic condition occurs by excretion of carbonic acid through rapid respiration and by excretion of hydrogen ions through urine. Affected cattle may survive through compensation, however, severe acidosis is fatal. Additionally, the increase in acidity of the rumen damages the mucosa which may result in necrosis of the epithelium which enables bacteria such as Spherophorus necrophorus to enter the veins and be conveyed to the liver where liver abscesses may form in surviving animals.
Lactic acid and products containing lactic acid have been found to enhance gains in the starting period of cattle (first 28 days) and reduce liver abscesses when given prior to the transition from a roughage diet to a feedlot diet. Various strains of Lactobacillus acidophilus have been isolated which restore and stabilize the internal microbial balance of animals. Manfredi et al, U.S. Pat. No. 4,980,164, is such a strain of Lactobacillus acidophilus which has been isolated for enhancing feed conversion efficiency. The Lactobacillus acidophilus strain of the Manfredi et al patent has been designated strain BT1386 and received accession number ATCC No. 53545 from the American Type Culture Collection in Rockville, Md. Strain ATCC 53545 demonstrates a greater propensity to adhere to the epithelial cells of some animals which would increase the bacteria cultures' ability to survive, initiate and maintain a population within an animal intestine. Thus, the primary mode of action as previously understood relative to Lactobacillus acidophilus occurs post-ruminally.
Another strain of Lactobacillus acidophilus isolated for restoring and stabilizing the internal microbial balance of animals is disclosed in Herman et al, U.S. Pat. No. 5,256,425. The Lactobacillus acidophilus strain of the Herman et al patent has been designated strain BT1389 and received accession number ATCC No. 55221 from the American Type Culture Collection in Rockville, Md. Strain ATCC 55221 is a further improvement on strain ATCC 53545 in that it is easily identified and quantified due to its resistance to antibiotics such as erythromycin and streptomycin.
The above-mentioned strains of Lactobacillus acidophilus are perfectly good lactic acid producing organisms. However, more than a lactic acid producing organism is needed to improve the utilization of feedstuffs by ruminants, especially during the transition from a roughage diet to a feedlot diet. The problem with the increase of D-lactate in the rumen must also be resolved in order to facilitate the transition of ruminants from a roughage diet to a feedlot diet.
Administration of bacteria to cattle is also problem due to the extreme sensitivity of organisms like Lactobacillus acidophilus which are difficult to maintain in a viable state at ambient temperatures. Also, lactic acid is corrosive to feedlot and feedmill equipment and metallic components
The present invention relates to a novel process which addresses the problems associated with the utilization of feedstuffs by ruminants which have been set forth above, especially the problems associated with the transition from a roughage diet to a feedlot diet.